News Release

MERCANTILE BANCORP, INC. RETAINS THE INVESTOR RELATIONS COMPANY

QUINCY, IL., December 8, 2005 - Mercantile Bancorp, Inc. (AMEX: MBR) today announced it has retained The Investor Relations Company for a full investor relations program.

Mercantile Bancorp, Inc. is a multi-state bank holding company headquartered in Quincy, Illinois. At September 30, 2005, the company reported unaudited total assets in excess of $1.11 billion, total loans more than $823 million and total deposits exceeding $931 million. Through its majority-owned subsidiaries, consisting of six banks in Illinois, two banks in Missouri and one bank in Kansas, the company conducts full-service commercial and consumer banking business, engages in mortgage banking, trust services, and asset management, and provides other financial services and products. In addition, the company has minority investments in four community banks in Missouri, Georgia and Florida.

“The Investor Relations Company will help us initiate a continuing effort to deepen existing investor relationships and broaden our investor audience," said Dan S. Dugan, chairman, president and CEO of Mercantile Bancorp, Inc. "The agency will play an important role in helping develop and deliver our message to our shareholders and the financial community at large."

MBR reported that for the nine months ended September 30, 2005 the annualized return on average equity amounted to 10.6% and the annualized return on average assets totaled .88%. Compared to December 31, 2004, total assets increased 7% to $1,112,891,000. Total loans, including loans held for sale, grew 6.7% to $823,621,000. Total deposits increased 6.6% to $931,286,000. During the same period, stockholders' equity increased 6.3% to $91,426,000, or 8.2% of total assets.

The company recently announced its approval of a quarterly cash dividend of six cents per share, and a special year-end dividend of 66 cents per share. The combined 72 cents per share is payable December 15, 2005 to stockholders of record at the close of business on December 1, 2005.

The Investor Relations Company (www.tirc.com) is a 24-year-old IR consultancy providing a full range of services nationally for small and medium size public companies with market values up to $2 billion.

This release contains information and “forward-looking statements” that relate to matters that are not historical facts and which are usually preceded by the words “may,” “will,” “should,” “could,” “would,” “plan,” “potential,” “estimate,” “project,” “believe,” “intend,” “anticipate,” “expect,” “target” and similar expressions. These forward-looking statements are subject to significant risks, assumptions and uncertainties. Because of these and other uncertainties, our actual results may be materially different from those described in these forward-looking statements. The forward-looking statements in this release speak only as of the date of the release, and we do not assume any obligation to update the forward-looking statements or to update the reasons why actual results could differ from those contained in the forward-looking statements.

Questions regarding this information should be directed to Mr. Dugan at (217) 223-7300, or by e-mail at investor.relations@mercbanx.com